All of the gas stations around where I live have the idiotic ethanol blend in all the pumps now.  I cannot find ethanol free gas anywhere close to here so this is what I have to use in my lawn equipment.  I've read before how some folks are putting small amounts of oil in their lawn mower fuel tanks to help alleviate knocks from the lawn mower engine.  I know my mower knocks pretty bad now that I have to use the ethanol garbage.  Any idea if the oil truly works and will not damage the engine?  If so, how much should I use?

I've heard some real knowledgeable small-engine guys advocate running two-cycle gas/oil mixtures in all small engines.
If it's necessary for a two-cycle it sure shouldn't hurt a four, although it may smoke a little more.

I've been running Stihl chainsaw gas in my four-stroke mowers recently; no problems so far.
If I burned tons of fuel, I'd probably further investigate cost/benefit ratio, though.
I don't really use much in a year.

What grade gas are you using while it is true that ethanol gas fucks up small engines I have not heard of any nor do mine knock due to it. I have however had that problem with the cheaper 87 octane gas and it quit when I switch to 93.

Did you check here- pure gas?

The problem with the alcohol gas in a naturally aspirated small engine is the alcohols affinity for water.  If the gas has been sitting in the tank for a few weeks, the blended fuel will "soak up" water, causing difficult starting.  After some time, there will be a layer of alcohol and water at the bottom of the tank that may burn, but very poorly.  



I would recommend finding a marina that sells pure gas.  


 

Just coming here to post this.

Also OP if you can find some PRI-G locally if you HAVE to go with E-10 that will help stabilize the gas.

PRI-G

Do not put oil in your gas, it will do nothing. If your engine knocks try a high octane gas.

Ive never had problems with ethanol and small engines.  One thing you DO want to do is use some ethanol stabilizer when the engine will be unused for long periods of time (like a boat at the end of the season, or a mower after fall) or else the ethanol will cause varnish.

The only things I have found to help with that bullshit gasoline is a stabilizer and higher octane gasoline.

Whether this is really a good solution...........I have no idea.

Start researching tcw3. It's used in marine 2 stroke engines,  and does a great job in regular car engines a well (in much lower doses)

You can buy a gallon of tcw3 oil for less than $15 and that should lady you a long time.
I get about 2500 miles out of a quart in my car.

I am not sure what it will do to the ethanol, but it will help lubricate and clean the fuel system. The fact that it's a marine oil probably says something to it's anti corrosion abilities.

I've been running two stroke gas in my four stroke engines for years with no problems whatsoever. I've been running leaded 110 octane race gas in my stuff for some time now. At eight bucks a gallon it's a pricey solution but that stuff NEVER goes bad, I let a mower sit for almost a year with that stuff in the tank, it started Second pull.

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The place I take my equipment tells everyone to run premix in everything.  He is not some shade tree mechanic....real deal place that all the contractors take their stuff too.  My mowers dont smoke......and run really good.  And I dont have to have two gass cans.

TCW3 is simply two cycle oil designed to work in water cooled engines, I would not recommend it in an air cooled app.

Again OP I would try a higher octane gas if you have knocking. You might consider some fuel additive like techron(sp?) to help clean the combustion chamber.

I repair and restore lawn mowers and here is my 2 cents.



The new ethanol gas will burn just fine in your lawn mower.



Now here is what you do NOT want to do.



Do NOT leave the gas in the mower after the season is over.  

Drain the tank then run until it dies.  Shake it and start again, or you can pull the bowl and drain it if your comfortable doing that.



The ethanol absorbs water from the ambient humidity in the air.  Gas is lighter than water, so it condenses at the lowest point of the fuel system, the carburetor bowl.

This water/alcohol mix forms a mild acid that will ROT your carburetor out.  I've seen carbs less than 1 yr old that look like they have been sitting in seawater.



So,



1. Treat your fuel with stabil or some type ethanol stabilizer

2. Do not store mower with an fuel in the system over the winter

3. Oil/Air Filter once a year for normal use.  Use SAE30 only please (unless Honda, then 10w-30)

4. Plug every 2 years

5. Sharpen blade as needed



These simple steps will keep your mower happy and running for a VERY long time.  My Snapper walk behind is 37yrs old and still chewing grass.



This is an example of my work, this mower was sold.

Before

 



After









Before





After







Did I mention that I like Snappers?